Dynamoelectric machine

ABSTRACT

A dynamoelectric machine with an axially symmetric rotor and shaft allows the rotor to be reoriented end-for-end within the machine. The machine includes an etched foil heating assembly, an indexable power conduit assembly, and a compartmentalized accessories conduit assembly selectively connected to the frame in a pre-determined manner. Bearing support assemblies for the rotor shaft incorporate adjustment blocks to permit ready alignment of mechanical and magnetic centers.

FIELD OF THE INVENTION

This invention relates to an improved dynamoelectric machine and, morespecifically, to a dynamoelectric machine wherein the rotor and certainother components may be re-arranged and re-oriented with respect to thestator and frame and with an improved support frame assembly, heaterassembly, power conduit assembly and accessories conduit assembly.

BACKGROUND OF THE INVENTION

Improved dynamoelectric machines are produced in a myriad of sizes andconfigurations varying from small, fractional horesepower to extremelylarge, multiple thousands of horsepower. For purposes of discussion,references will be made here only to integral horsepower alternatingcurrent (AC) induction motors which are in the range of about 500 to atleast generally about 10,000 horsepower. Machines or electric motors ofthis power range are generally not custom machines, i.e., they aregenerally available from a motor manufacture by specifying requiredhorsepower, shaft RPM and voltage rating. Electrically, however,variations among these three specifiable variables can result in manydifferent arrangements within the motor armature and stator. Inaddition, since motor speed or shaft RPM is determined by the number ofpoles, the mechanical structure of the rotor (on which the armaturewindings are carried) and the stator are varied, not only by the numberof poles but also by the physical size of the stator and rotor necessaryto support those poles.

Many attempts have been made to overcome the difficulty associated withthe many variations in motor arrangements by some form ofstandardization. U.S. Pat. No. 2,543,131 discusses the standardizationproblem and addresses the need to provide a terminal block which canfacilitate changing from a lower voltage to a higher voltage and from afirst speed to a second speed by changing the connections at the blockfor variations in Delta and Wye connections. However, such anarrangement addresses only a single speed change and voltage change andwhile useful, does not address more extensive problems instandardization.

It is desirable, therefore, to provide a machine which incorporates aplurality of features interchangeable between machines of a differentsize or specification. It is desirable, for example, to provide heatingdevices which are useable to prevent moisture from condensing into suchmachines during a cool down cycle, which devices are applicable to anysize machine by varying their number It is desirable to provide amachine symmetrically constructed with respect to the rotor such thatthe frame and stator can be positioned in a desired orientation and therotor inserted with a drive end selectively positioned. It isadditionally desirable to provide a frame assembly for a machine inwhich the orientation of a power conduit box may be selectively changedand in which the location of the power conduit box and an accessoryconduit box are variable. It is also desirable to be able to adjust therotor position in such a machine to align mechanical and magneticcenters.

Accordingly, it is an object of the present invention to provide animproved dynamoelectric machine and a method of re-arranging andre-orienting components which provide at least the desirable featuresidentified above.

It is another object of the present invention to provide an improvedrotor mounting arrangement which allows rotor position to be variedaxially for mechanical alignment in such improved dynamoelectricmachine.

It is still another object of the present invention to provide a methodand apparatus for rearranging and re-orienting the relative position ofthe rotor and stator in such improved dynamoelectric machine.

SUMMARY OF THE INVENTION

The present invention combines a plurality of improved features toextend the universal operability of dynamoelectric machines, includingby way of example an alternating current (AC) split phase, inductionmotor. Among such improved features are the design configuration of therotor and stator of an AC motor to provide for reversibility of therotor with respect to the stator. Other improved features include theshaft end supports; shields for the shaft bearings; heater; powerconduit assembly; accessories conduit assembly; and various combinationsof such assemblies, subassemblies and elements. And while the presentinvention is described in terms of its preferred embodiment, an electricmotor, it should be readily understood that the various inventivefeatures of such assemblies, subassemblies and elements and variouscombinations thereof are equally applicable to other structures,including by way of example, generator structures.

For the purpose of summarizing the present invention, the invention inone form thereof may be incorporated into a improved dynamoelectricmachine comprising a frame having spaced end portions and side panelscoupling the end portions. The end portions have fixed lower supportssecured with respect to the side panels. The end portions also havingupper shields removable from the lower supports and the remainder of theframe. A stator is fixedly mounted about its axis within the frame inoperative proximity to a rotor. An essentially cylindrical shaft isrotatable about its axis and supports the rotor for concurrent,concentric rotation therewith. The shaft is supported adjacent its endsby the lower supports. The rotor and shaft are symmetric about a planepassing radially therethrough midway of the end portions. Releasablecoupling means selectively couple and uncouple the upper shields fromthe lower supports to thereby facilitate the removal and replacement ofthe rotor and shaft either frontward or backward with respect to thestator and the frame. A generally rectangular power conduit assembly hasattachment means to releasably attach the power conduit assembly to oneof the side panels. The power conduit assembly has a square aperturetherein in communication with a generally square aperture in one of theside panels to allow the passage of leads between the interior of thepower conduit assembly and the interior of the frame. The power conduitassembly also includes an additional aperture to allow the passage ofleads between the interior of the power conduit box and a source ofelectrical power. The attachment means is adapted to couple the powerconduit assembly to one of the side panels with the additional aperturefacing selectively, either upwardly, downwardly or to either side. Anaccessories conduit box is fixedly secured to one of the side panels. Aplurality of insulating terminal blocks are located within theaccessories conduit box each with conductive terminals for receivingleads coupled to sensors which monitor various operating parameters ofthe machine. Separation means isolate the blocks and the terminals intoa plurality of electrically discrete compartments. At least some of thecompartments are adapted to support blocks and terminals only of apredetermined electrical characteristic. An improved heater including aplurality of low temperature, constant temperature elements encasedwithin heat sinks whereby the heat output thereof will not exceed apredetermined maximum temperature as a function of the voltage suppliedis provided to control temperature within the motor frame when the motoris not operating.

As will become apparent, the above generalized features each provide forstandardization and modularity for a family of motors covering a broadrange of speed and horsepower requirements. Although standardization andmodularity is always limited to commonality within a range of motorcharacteristics because of physical size limitations involved indeveloping additional horsepower, the improvements disclosed in detailbelow will be recognized as having a braod range of applicability.

DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, reference may behad to the following detailed description taken in conjunction withaccompanying drawing in which:

FIG. 1 is a perspective illustration of a dynamoelectric machine in theform of an alternating current motor constructed in accordance with theprinciples of the present invention;

FIG. 2 is a perspective illustration of the motor shown in FIG. 1 viewedfrom the opposite side and end;

FIG. 3 is a perspective illustration of the motor of FIG. 1 with the airconditioning plenum removed;

FIG. 4 is a perspective illustration of the motor of FIG. 3 with anaccessory box and a power connection box selectively located in apredetermined manner on a common side;

FIG. 5 is a perspective illustration of the motor shown in FIG. 1 butwith certain parts exploded away and with yet other parts broken away toillustrate certain internal constructions of the motor;

FIG. 5A is a partial cross-section of FIG. 5 showing the heaterassembly;

FIG. 6 is a sectional view of the motor shown in FIG. 5 taken radiallythrough the machine and through the power conduit assembly andaccessories conduit assembly;

FIG. 7 is an alternate electrical schematic diagram of one windingconfiguration for a stator for the motor of the present invention;

FIG. 8 is a front sectional view of the power conduit assembly andcoupled leads from the stator windings and power source for anindependent stator connection arranged in a Delta configuration;

FIG. 9 is a sectional view of the power conduit assembly of FIG. 8 butviewing the leads and terminals from a side elevational view;

FIG. 10 is a front sectional view of the power conduit assembly andcoupled leads from the stator windings and power source for anindependent stator connection arranged in a Wye configuration;

FIG. 11 is a sectional view of the power conduit assembly of FIG. 10 butviewing the leads and terminals from a side elevational view;

FIG. 12 is an electrical schematic illustrating the coupling of thestator power supply leads in the power conduit box in a Wye connectionfor the wiring configuration of FIGS. 10 and 11;

FIG. 13 is an electrical schematic illustrating the coupling of theleads in the power conduit box in a Delta connection for the wiringconfiguration of FIGS. 8 and 9;

FIG. 14 is a sectional view of the shaft and a bearing taken verticallyalong and through the axis of the shaft and bearing;

FIG. 15 is an exploded perspective illustration of a cooling assembly;

FIG. 16 is a partial cross-sectional view taken through the motor andcooling assembly of FIG. 15;

FIG. 17 is a side elevational view of the power conduit assembly of themotor shown in FIGS. 1-5 with parts broken away to show certain internalconstructions;

FIG. 18 is a front elevational view of the power conduit assembly shownin FIG. 17 with parts broken away to show certain internalconstructions;

FIG. 19 is a bottom view of the power conduit assembly shown in FIGS. 17and 18 but with parts broken away to show certain internalconstructions;

FIG. 20 is a front elevational view of the accessories conduit assemblyas shown in FIGS. 1 and 5 with the door removed; and

FIG. 21 is a sectional view of the accessories conduit assembly as shownin FIG. 20 and taken along line 21--21 of FIG. 20.

Throughout the drawings, similar numbers will refer to similar parts.

DESCRIPTION OF THE PREFERRED EMBODIMENT

General Overview

Referring now to FIG. 1, a preferred embodiment of the present inventionillustrates a dynamoelectric machine, such as for instance analternating current (AC) induction motor or the like, although it willbe appreciated that the general description will also apply to otherdynamoelectric machines, e.g., synchronous motors. In general terms, themotor includes a rotor assembly and a stator assembly supported by andencased in a frame or a frame assembly formed of rigidity impartingframes surrounded by appropriate external supports, panels and shields.

In FIG. 1, the motor includes an air conditioning plenum 10 forprocessing cooling air within a frame or frame assembly 12. Mounted inthe frame assembly 12 is a stator or stator assembly 14 and a rotor orrotor assembly 16 (best seen in FIG. 5). A power take-off shaft or driveend 18 is an extension of a shaft 28 on which the rotor 16 is mounted.Attached to a side of the motor is an accessory box or accessoriesconduit box 20 which provides convenient termination and connectionpoints for various condition sensors associated with the motor. On theend of the motor frame assembly 12 can be seen an upper end shield 54which can be readily removed to allow viewing of internal portions ofthe motor.

The structure of rotor 16 includes a standard cylindrical bodyconcentric with respect to an axis of rotation of the shaft whichsupports it. The shaft is supported adjacent its ends by oppositebearing members 26 held, in turn, by end supports or lower end shields56 to thereby allow rotation of the shaft and rotor concentrically andconcurrently. Both the rotor and the stator are wound with insulatedwires in a manner well known in the art to convert the input electricalpower into mechanical power at the power take off end 18 of the shaft.

A heating assembly 106, as shown in FIGS. 5 and 5A, is provided withinthe frame assembly 12 of the motor to prevent moisture/condensation fromforming upon cooling after use. This is desirable in order to precluderust-causing moisture from deteriorating the operating components of themotor. The source of heat is preferably low temperature, constanttemperature resistance elements, such as for instance an etched foilheater encased in a heat sink such as anodized aluminum. This assemblypreferably includes a plurality of groups of heating elements locatedbeneath the stator and rotor with a planar face positioned generallytransverse to a radius of the rotor and shaft.

The cooling assembly or air conditioning plenum 10, which constitutesthe upper part or portion of the motor, detachably mounts to the top ofthe frame assembly 12. It has an open lower surface in flowcommunication with an open upper surface of the frame assembly 12. Thecooling assembly 10 in one embodiment includes an air-to-air heatexchanger whereby a sealed flow of air within the motor may berecirculated from the heat generating mechanisms of the motor, e.g., therotor, stator, shaft and bearings, to the air-cooling conduits of theheat exchanger and back again in a continuous and recirculating path ofmotion. Fans (shown in FIG. 5) provide the impetus to effect circulationof the air.

FIG. 2 is a reverse view of the motor of FIG. 1 and particularlyillustrates the positioning of a power conduit assembly 24. The powerconduit assembly 24 and the accessories conduit box 20 are eachphysically secured to a side panel or panels of the frame assembly 12.The power conduit assembly 24 includes electrically conductive connectorbrackets and an electrically conductive bus bar whereby the variouselectrical leads from the stator may be attached and coupled with powerleads from the external source of electrical power. The power conduitassembly 24 has an external aperture or door openable to expose thevarious internal leads and terminals whereby an operator may alter theinterconnection of the leads from both the source of electrical powerand from the stator windings so that the operational characteristics ofthe motor might be modified. For example, an originally coupled Wyeconnection might be changed to a Delta connection or vice versa. Themodification might also include the changing of the source or nature ofthe power supply, e.g., from 2300 VAC to 4000 VAC. Additionally, thepower conduit assembly 24 may be reoriented with respect to the frameassembly 12 by indexing it in 90 degree turns to accommodate power leadsentering from above, below or from either side.

The accessories conduit box 20 is provided with insulating terminalblocks with conductive connectors for the appropriate coupling of wiressupporting various or selected sensor or sensor means, such as forinstance probes, monitoring devices, heaters, etc., within the motor.The accessories conduit box 20 is divided into several compartments withthe higher voltage power leads being exposed in one compartment and withthe lower voltage signal leads being exposed in another compartment. Thepositioning of at least some of these various leads is variable at thediscretion of an operator. However, the power leads of higher voltageare maintained in a separate compartment from the signal leads of alower voltage. Readouts, as for certain temperatures including cut offand trip temperatures, as well as permanently coupled proximeters forvibrations may also be provided.

A closure or door on the accessories conduit box 20 shields theterminals and their wires during motor operation and use. The readoutsare preferably located on the door or cover for convenient viewingwithout opening. Wireways or channels are also provided with open andclosed sections so that the power leads are not exposed in the signalleads compartment and so that the signal leads are not exposed in thepower leads compartment. Among the signals being detected are thevibrations at the bearings and temperatures at key motor locations.Among the powered features are humidity dissipating heaters, thermostatsand switches.

Because of the general configuration of the motor, its position may bereadily reoriented in the field. By this it is meant that if, for anyreason, the user might wish to relocate the power conduit assembly 24and accessories conduit box 20 on the side of the machine opposite fromits original orientation, such a modification may be readilyaccomplished. In such a situation, the user would remove the upper endshields 54 and the lower end supports 56 from both ends of the motor anduncouple the shaft 28 from the mechanisms being driven (not shown). Therotor could then be slid axially from the remainder of the frameassembly 12. The frame assemby 12 with stator 14 could be then rotated180 degrees, i.e., half of a full rotation. This rotation would placethe power conduit assembly 24 and accessories conduit box 20 on oppositesides with respect to their original orientations. The rotor would thenbe slid axially back into the motor and the shaft recoupled with thedriven mechanisms. The lower end supports and upper end shields couldthen be replaced to complete the desired modification.

Such reorientation of the rotor with respect to the frame and the statoris made possible since the rotor and shaft are symmetric about a planepassed radially through the rotor and shaft midway between the lower endsupports and bearings.

The cooling assembly 10 which constitutes the upper part of the motorneed not be uncoupled from the frame of the motor during thisreorientation. In such situations, however, where a superior, cooling,ambient air exists at one end of the motor or other, it is possible touncouple the cooling assembly 10, reposition it one-half of a turn,i.e., 180 degrees, and then recouple it to the frame assembly 12 of themotor. In this manner, it is still possible to take advantage of thepreferred source of cooling ambient air.

Another situation where it might be desired to rearrange and re-orientthe rotor end-for-end with respect to the stator would be where it issought to power a differently positioned mechanism or to power the samemechanism but from a different side without changing stator position. Insuch situations, the reorientation would be accomplished by removing therotor 16 and repositioning it 180 degrees, i.e., end-for-end, withrespect to the stator. The power conduit assembly 24 and accessoriesconduit box 20 would then remain in their original position.

Referring briefly to FIGS. 3 and 4, there are illustrated twoalternative arrangements of the power conduit assembly 24 and accessorybox 20. In FIG. 3 the accessory box 20 is located on a side of the motoropposite the side to which the conduit assembly 24 is mounted. In FIG.4, both the assembly 24 and box 20 are selectively placed on the sameside of the motor. As will become apparent, in order to place bothassembly 24 and box 20 on a common side, a modification of box 20 isrequired.

Rotor and Stator Assemblies

Turning now to FIG. 5, the partial exploded view of the inventive motorillustrates, among other features, the mounting and positioning of thestator 14 and rotor 16. As well known in the art, rotor 16 has agenerally cylindric circumferential surface interposed between a pair ofgenerally opposite end faces although only one opposite end face of therotor is shown in FIG. 5 for the purpose of drawing simplification, andin general terms, the rotor 16 and stator 14 are supported by, andencased in, the frame assembly 12 formed of rigidity imparting framemembers surrounded by appropriate panels and the like to enclose therotor, stator and other operating elements. The bearing assemblies 26for supporting shaft 28 which, in turn, supports the rotor 16 forrotational movement concurrently and concentrically together, issupported in turn on lower end supports 56 for allowing the smooth,friction-reduced rotation of the shaft 28. Thus, rotor 16 and shaft 28comprise the rotatable or rotor assembly. The stator 14 is fixedlypositioned within the frame assembly 12 through suitable brackets.

The rotor 16 and the stator 14 are each individually formed with currentconductors in a manner well known in the art to convert the inputelectrical power into mechanical power. In one type of motor, theconductors of the rotor 16 are supported on a squirrel cage cylinder.The conductors are essentially lineal bus bars running parallel to theaxis of the rotor for interacting with the electrically rotating fieldpoles of the stator 14 for converting the electrical energy input to thestator windings into mechanical energy for driving a mechanicalmechanism coupled to the power take off shaft 18.

The windings of the stator 14 are formed individually and assembledoutside the frame assembly 12 into a complete stator 14. The windingsare of a type well known in the art comprising plural wires orconductors which are formed on multiple stator laminations punched froma ferromagnetic material, such as for instance silicon steel, which arestacked and compressed to form the of the stator. Albeit not shown, thewindings of the stator 14 may be oriented in any one of a plurality ofelectrical configurations, and such stator windings may have any evennumber of electrical poles desired which may be utilized in differentdesired numbers of circuits. Three phase power may be connected as inputeither through a Delta or Wye connection. Depending on the configurationof the poles, circuit, phase and connection, the operatingcharacteristics of the motor may thus be modified.

Certain types of changes to the operating characteristics of the presentmotor may be effected at the power conduit assembly 24. Such changesmight include reconnections for different applied voltages or might bein the connection configuration utilized, as for example, whether thepower is applied through a Delta or Wye type of connection. Changes moreextensive than these, such as the number of electrical poles, number ofcircuits, number of phases, or the like, are not normally field changesand would require internal circuit changes or further changes within thestator.

FIG. 6 is a sectional view of the motor which illustrates the mechanicalarrangement of the leads 32 from the stator windings to the powerconduit assembly 24. This Figure also shows some of the wire leads 34from the accessory box 20 to the motor. Each of these elements will bediscussed in more detail below.

FIG. 7 is an electrical schematic illustration of a representative orstandard stator wiring diagram with five slots per pole per phase.Although a great number of wiring diagrams might be utilized, this oneis shown and described for illustrative purposes only. In this standardstator wiring diagram well known in the art, the leads brought out fromthe stator windings are consecutively numbered 1L-24L, and all suchleads having the same circled letter or same circled letter and numbernotation are interconnected with each other. FIG. 7 is a four pole, twocircuit, three phase configuration. Both ends of all three phases,indicated by terminals T1-T6, are brought into the power conduitassembly 24 to permit connection of the stator winding in a Wye or Deltaconfiguration, as illustrated in FIGS. 12 and 13 and further discussedhereinafter. This type of arrangement is referred to as an independentstator connection.

FIGS. 8 and 9 are mechanical views illustrating the connections of theleads at the power conduit assembly 24 for a Delta connection. FIGS. 10and 11 are mechanical views illustrating the connections of the leadsfrom the stator windings in a Wye connection. FIGS. 13 and 12 illustratethe electrical lead couplings at the power conduit assembly of FIGS. 8and 10, respectively, in electrical schematic illustrations.

Frame Assembly

As can best be seen in FIG. 5, the entire motor is supported by frameassembly 12 which includes frame pieces such as axial side bars 34 ofheavy strength sheet material, transverse end plates or end portions 36,and a bottom sheet member 38 of similar rigid construction. As usedherein, the terms axial and transverse are intended to mean in thoseorientations axial and transverse with respect to the axis of the shaft28. These frames pieces are welded together adjacent their common edgesto create a rigid frame for the various internal components of the motoras will as the other supports, panels and the like. The sides of themotor are covered by side panels 39 which may be of a lesser gauge steelplate and are preferably welded to the frame pieces at theirperipheries. Located on the faces of both of the side panels 39 arelower apertures 40 to provide for access to mounting and leveling studs42. A cover plate 44 is provided on each side in association with eachof these lower apertures for sealing the internal components of themotor for safety and cleanliness purposes. The plates 44 are held inplace by screws to allow for their convenient attachment and removal.

Additional rigidity is supplied to the motor frame assembly 12 throughthe use of vertical, transverse support plates 46 which areappropriately shaped to permit the positioning of the stator 14 withinthe frame assembly 12. Further braces 48 pass axially through aperturesin the transverse support plates 46 and are attached to the end plates36 while additional cross braces 50 are supported perpendicular tosupport plates 46 for joining the side panels 39. These braces 48,50 areso configured as to allow operator access to internal components of theframe assembly 12 through the open upper face thereof when the coolingassembly 10 is removed. The cross braces 50 are also positioned andconfigured to define the appropriate path of travel of cooling airbetween the tubes of the air-to-air heat exchanger of cooling assembly10 and the heat generating mechanisms of the motor. Angled brackets 52are provided along the lower face of the machine to provide additionalrigidity to the frame assembly 12.

The end plates 36 of the frame assembly 12 include generally axiallyaligned openings or passage means 36a through which rotor 16 and shaft28 may be passed upon the reorientation thereof as previously mentioned,and the openings are preferably closed by two piece end shieldarrangement with each such arrangement having a readily removable upperend shield 54 formed as a vertical panel which is mounted above a lowerend support 56 accommodating the ends of the shaft 28. Suitablereleasable coupling means, such as for instance a plurality of screws orbolts or the like, extend through a plurality of apertures 60 in aflange 58 on upper end shield 54 for releasably securing or attachingthem to the end plates 36 of the motor, and other such releasablecoupling means extend through other such apertures (not shown) in lowerend support 56 for releasably securing or attaching them to the endplates of the motor. More particularly, the window 62 is aligned with aviewing window in bearing assembly 26 to permit inspection of bearinglubrication without disassembly. Additionally, general torus shapedstator end turn shields 64 are mounted to internal vertical transversesupport plates 46 adjacent the windings of each end of the stator 14.Although only one stator end turn shield 64 is shown only at one end ofthe motor, it should be understood and appreciated that a complementarystator end turn shield of similar design is located on the opposite sideand end of the motor.

Referring briefly to FIGS. 1 and 2, it can be seen that theaforementioned two piece end shield arrangement is substantiallyidentical on each end of the frame assembly 12, the difference betweeneach end lying only in the generally circular cover plate 66 arrangeddistal from the power take-off shaft end 18. In order to provideaccurate and structural support for the shaft, lower end supports 56 maybe constructed of heavy gauge metal reinforced with struts 68. Thebearing assemblies 26 are mounted to and supported by lower end supports56. These lower end supports 56 along with the upper end shields 54 arereleasably secured to end plates 36 generally about openings 36atherein, as previously mentioned, and must be removed prior to theremoval of the shaft 28 and rotor 16 through one of the openings 16. Ahorizontal flange 70 is rigidly secured, as through welding, to theupper edge of each lower end support 56, and the flange is appropriatelymachined and shaped for the reception of the bearing assembly 26.

A generally annular cover plate 72 is formed with an aperture throughwhich the power take-off shaft 18 may pass during operation and use ofthe motor, and the annular cover plate is appropriately bolted insecurement to the end support 56 and the bearing assembly 26. At theopposite end of the motor there is provided circular plate 66 which isbolted to the end support 56 for appropriately sealing off this end ofthe motor.

Bearing Assembly

The bearing assembly 26 is duplicated at each end of frame assembly 12for supporting the shaft 28 at opposite ends of the motor. Referring nowto the cross-sectional view of FIG. 14, each bearing 26 includes atilting sleeve bearing pad 74 through which the shaft 28 passes and bywhich the areas of the shaft adjacent its opposite ends are supported.The bearing is provided with an internal split bearing shell 76 of upperand lower sections apertured for the passage of rotatable oil splashrings 78. At its upper extent, each oil splash ring is exposed forobservation by an operator to verify its movement during operation anduse.

During operation and use of the motor, the shaft 28 will rotate whilethe bearing shell 76 remains fixed. Rotation of the shaft 28 will rotatethe oil splash rings 78 in a path of movement to continuously bringsequential segments of the splash ring laden with oil from oil bath 80to thereby lubricate the shaft 28 at its interface with the internalsurface of the bearing pad 74. Continued rotation of the shaft andsplash rings 78 can thus be observed as sequential sections of the ringexpose themselves above the bearing shell 76 for viewing by theoperator. Viewing is achieved through a fixed bearing cap 82 having aviewing aperture 82a therethrough and a transparent window W locatedtherein. In the event of a seizure of the oil ring 78 as viewed throughthe aperture in the bearing cap 82 or for other lubricationmalfunctions, such condition can be observed by the operator andcorrective action taken.

Inner oil seals 88 are provided as rings in cutout sections of thebearing shell 76. Outer oil seals 92 are provided externally of thebearing shell with the bearing cap 82 located therearound to completeeach bearing assembly.

An antirotation pin 96 secures together the internal bearing shell 76and the external bearing cap 82 against rotation with respect to theshaft and with respect to each other. An endplay adjustment block 98 isalso provided for permitting alignment of mechanical and magneticcenters of the motor. Other elements within each bearing are oilslingers 100, a thrust plate 102, and for the power take off end only, agrounding screw 104. A bearing temperature sensor 84 positioned in pad74 provides a signal representative of bearing temperature while aproximity probe 86 provides an output signal representative of shaftvibration as evident by variations in spacing between shaft 28 and probe86.

As mentioned previously, upper end shield 54 includes a view window 62aligned with the aperture and window in the bearing assembly to permitexamination of bearing assemblies 26 without disassembly. The windowsmay be formed of tempered glass or other transparent material. Thesewindows allow the operator to view the bearing assembly 16 and, moreparticularly, the oil splash rings 78 of each bearing during operationand use of the motor without removing any motor component.

The end-play adjustment block 98 allows the bearing assembly to beadjusted relative to the motor frame assembly 12. Since the rotor ispositioned by the bearing assemblies, the effect of the adjustment block98 is to shift the position of the rotor with respect to the statorwhich is attached to the frame assembly. This realignment of themechanical position of the rotor is necessary in order to force themechanical center of the rotor to be aligned with the magnetic center.In general, the rotor is provided with approximately one-half inch ofend play to allow the user to shift the power take-off shaft 18 slightlyfor alignment with external equipment and to allow some motion of theshaft to compensate for thermal shifts in position. During manufactureand testing, the magnetic center of the motor is determined and markedon the shaft for subsequent referral by a motor user. Since the shaftwill tend to move to the magnetic center during operation, the usernecessarily is forced to align the shaft to the magnetic center positionin order to avoid any thrust type of forces being placed on either thedriven equipment or on the shaft of the motor itself. As will beappreciated, if the mechanical center does not coincide with themagnetic center, the allowances for shaft movement, i.e., end play, maynot be plus or minus 1/4 inch but may in fact be plus 7/16 inch andminus 1/16 inch. In such situations, thermal shift of the shaft duringoperation may cause a shoulder on the shaft to contact the bearingassembly resulting in damage to the motor. The adjustment blocks 98include a plurality of shims 99 which can be taken from one of theblocks and added to the block at the other end of the shaft in order toshift the mechanical center of the rotor. The adjustment blocks providean advantageous method of aligning the mechanical and magnetic centerswithout requiring disassembly of the bearing assemblies in the motor inorder to locate the bearings at the proper position.

Heater Assembly

A plurality of heating assemblies 106 are provided within the frameassembly 12 to prevent condensation from collecting on the components ofthe motor when it is shut down after operation. At least two of theheating assemblies 106 can be seen with reference to FIG. 5 and eachincludes a resistance element 108, a heat sink 110 and a support. Poweris supplied to the resistance elements 108 of the heater from theaccessory conduit box 20 through appropriate power leads. The heatingresistance elements 108 are preferably configured to such dimensions asto maintain a predetermined low, constant temperature regardless of thetime the electrical power is supplied thereto. An appropriate materialfor such resistance elements is an etched foil of a thermal andelectrical conductor which can be bonded to a face of an insulatingsupport such as bakelite, a ceramic, a thermosetting plastic or similarmaterial. The bonding may be effected as is common in printed circuitboard technology.

A more detailed view of a heating assembly 106 may be had by referenceto FIG. 5A which is a cutaway sectional drawing of that portion of FIG.5 containing a heater assembly 106. As is shown, each heater issupported by a brace 105 having a pair of cantilevered arms 107 whichsupport and position the heater substantially perpendicular to a radiusof the stator. The brace 105 is attached to a bar 109 by welding,clamping or other means well known in the art.

Surrounding each resistance element 108 is heat sink 110 fabricated, forexample, of anodized aluminum. The internal surface of the aluminumcorresponds in cross-section of a shape preferably the same as theexternal surface of the resistance element, rectangular in the disclosedembodiment. The selection of the etched foil resistance element ispreferred over prior art materials as, for example, Calrod surfaceheating unit type material which continuously increases in heat outputas additional electrical power is applied over time.

In prior art heaters, such as those described above, there was atendency of the heating elements to go far beyond the temperaturesdesired for the present application. Thermostats have been used to holddown such temperatures by cycling. Alternatively, another approachincluded increasing the length of the heating element to therebydecrease the heating current. This allowed the heater to operate atlower temperatures. Unlike the present invention, however, the prior artstructures required increases in costs of materials to yield lesserthermal outputs. Such prior art deficiency is not present in the instantinventive heating assembly 106. The advantage of the etched foilresistance element 108 is that it can be engineered and designed not toexceed a predetermined temperature as, for example, 120 degreesCentigrade in the preferred embodiment of the invention, regardless ofthe time the particular voltage is applied thereto.

The need for heaters 106 occurs after the motor has been turned offfollowing continued usage. During the time of operation and usage, heatis generated by the electrical power and mechanical rotating elements.Upon turning off the motor, the internal heat rapidly becomes dissipatedand moisture condenses out of the air and can deteriorate variouscomponents of the motor, including electrical insulation and metallicsurfaces. The use of the heaters for a preselected time tends tominimize the condensation problem and, thereby, extend the life of themotor.

Power to the heater assemblies 106 is from the accessory conduit box 20and may be manually activated and inactivated. In the alternative, itcould be automatically actuated through a thermister or othertemperature sensor. It could also be cut off when a particular reducedtemperature is reached or it could be cut off through a timed activationand inactivation if the normal operating parameters of the machine andenvironment were understood.

In practice, groupings of such heaters 106 have been provided within theframe assembly 12 of the motor secured through appropriate angledbrackets to a bottom frame member of the motor. The angling, generallyperpendicular to a radius of the rotor and stator, will present amaximum surface area to the stator 14. By placing the groups of heatingelements adjacent the bottom of the motor, heat will be directly appliedfirst to the lower regions of the motor and will rise upwardly to mostefficiently effect the heating of the motor and evaporation of themoisture as required. Such groups of heaters are preferably locatedbeneath the rotor and stator with two groups at each end of the motorand with two groups of heaters on each side of the motor.

Cooling Assembly

Among the other operational assemblies of the machine is the coolingassembly or air conditioning plenum 10 which mounts to the top of theframe assembly 12 of the motor. The lower surface of the coolingassembly 10 is in flow communication with the open upper surface of themotor as shown in FIGS. 5 and 17.

The cooling assembly 10 illustrated in FIGS. 1 and 2 may be either aNEMA weather protection type (1) or type (2) enclosure. In suchenclosures, the internal fans within the motor attached to the shaft 28serve to force air to be pulled in through the enclosure and down intothe motor and then blown back outwards through the louvers in the sidesof the enclosures. The NEMA standards dictate the number of bendsthrough which the air must pass before entering the motor depending uponthe type of weather protection desired. FIG. 5 also shows the same typeof cooling assembly as is shown in FIGS. 1 and 2. The cooling assemblyillustrated in FIGS. 15 and 16 is referred to as a totally enclosedair-to-air cooling assembly and is arranged somewhat differently thanthe aforementioned NEMA weather protection type (1) or type (2) coolingassemblies. In particular with reference to FIG. 16, it can be seen thatthe motor shaft 28 includes an additional extension 28A passing throughthe lower end support 56. An additional fan 150 is mounted on the shaftextension 28A. The fan 150 is enclosed in a fan casing 152 which ismounted on the end of the motor. For this type of arrangement, the endshield 54 is removed from the end of the motor to which the fan 150 isattached. The fan casing 152 then provides the enclosure for the end ofthe motor and also provides an air directing conduit for air pulled inthrough the louver assembly 144. The fan casing 152 and louver assembly144 are shown disassociated from the motor in FIG. 15.

The cooling assembly of FIGS. 15-16 is an air-to-air exchanger whereby asealed flow of air within the motor may be recirculated from the heatgenerating mechanisms of the machine--the rotor, stator, shaft,bearings, etc.--to the air cooling conduits 116 of the heat exchangerand then back again in a continuous and recirculating path of motion.This path of movement is indicated by the arrows 140 of FIGS. 15-16.

The cooling assembly 10 of FIG. 5 is formed of an external rigid framemember 118 as of sheet metal in a generally rectangular configurationwith louvers 120 on the four opposing vertical faces and with anenclosing sheet metal roof 124 thereabove. The totally enclosed coolingassembly of FIGS. 15-16 has a similar external frame construction butwithout louvers. The cooling assembly has a sheet metal top 128, closedsides 130 and closed end 126. The lower face is open while verticaltransverse braces 132, 134 and 136, divide the internal air flow intopaths of travel as indicated by the arrows 140.

Fans 142 attached to shaft 28 direct the air flow around the interiorvertical braces within the confines defined by the chamber of thecooling assembly 10. The air is directed upwardly at the central sectionof the motor to bring the heated air to the central section of the airconditioning assembly 10 past the plurality of cooling conduits 116 ofthe air-to-air condenser. This air is sealed or otherwise containedwithin the motor solely for cooling purposes. The air flow can best beseen by reference to FIG. 16. The air passes through passageways 138above the interior vertical braces 132 and 134 then downwardly and againpast the heat exchanger conduits 116. The air flow is then passed orcirculated into the interior segments of the motor to cool bydissipating its heat. Cross support members 50 at the upper section ofthe motor and stator winding end turn shields 64 guide this path of flowof the cooling air.

The exterior plate 146 of the cooling assembly provides for terminationand support of the cooling conduits 116. At the first, or air input, endan air inlet chamber 148 is located for receiving ambient air forpassage to and through the sets of cooling conduits 116. The fan 150within the fan casing 152 draws air in through louver 144 and forces itthrough conduits 116. The heated air from the motor passes by theconduits at least twice and is cooled by such contact. As best seen inFIG. 16, the air from the motor is forced into the center section of thecooling assembly between the plates 132 and 134 by the fans 142 on therotor shaft 28. The air circulates over the plates 132 and 134 andre-enters the motor.

An enlarged apertured plate 156 with downwardly turned flanges issecured to the lower face of the cooling assembly. A horizontal extentof its periphery is provided with holes for being bolted to the upperedges of the frame assembly 12. This plate secures the external framewith respect to the cooling assembly for attachment to the lower part ofthe motor. The plate 156 is essentially the same in each embodiment ofthe cooling assembly, differing only in size since the totally enclosedmotor has the fan casing 152 which effectively lengthens the motor.

Power Conduit Assembly

As shown in FIGS. 2, 3, 4 and 6, mounted on one side panel 39 of themotor is the power conduit assembly 24. The power conduit assembly 24 isadapted to provide the location and elements for coupling the leads fromthe stator 14 with the leads from a source of electrical power.Referring to FIGS. 17-19, the power conduit assembly 24 includes a powerconduit box 158 generally rectangular in configuration with rectangulartop and bottom faces 160 and 162, side faces 164 and 166 and front andback faces 168 and 170. These faces are generally welded together orotherwise secured to constitute a rigid structure. The front faceincludes a panel 172 removably secured to inturned flanges of the top,bottom and side faces. The removable panel constitutes a door to provideeasy operator access to interior of the power conduit box.

The power conduit assembly 24 also includes a minor extension 174 weldedto the power conduit assembly over or generally about an aperture 176 inthe back face 170 of the power conduit assembly. On the opposite end ofthe minor extension 174 are inturned flanges with an aperturesymmetrically matched to an aperture in a side panel of the motor frameassembly 12. Fastener holes of the minor extension 174 are symmetricallylocated and are provided on each of the four flanges so that the powerconduit assembly 24 might be indexed 90 degrees, 180 degrees or 270degrees from the orientation as shown. Fasteners, such as steel bolts,would be removed and reapplied to allow this securement at thediscretion of an operator.

Referring to FIG. 17, positioned at the bottom face 162 of the powerconduit assembly 24 is a smaller aperture 178 for permitting the passageof power leads from a source of electrical power to the interior of thepower conduit assembly 24. The indexing of the power conduit assembly24, as described above, will permit the appropriate positioning of thepower line aperture 178 and power conduit box most conveniently withrespect to the location of the incoming power leads for coupling to themotor leads. As shown in FIGS. 18 and 19, there are provided brackets183 to which the power connection terminals may attach. Referring toFIGS. 10 and 11, the stator winding terminals T4, T5 and T6 areconnected by a bus bar 188 which is attached to the brackets 183 bymeans of insulators 186. The terminals 182 connecting the stator leadsto incoming power leads are fabricated of electrically conductivematerial, preferably copper, and apertures are provided in the terminalfor the attachment of the leads from the source of power as well as fromthe motor. To form the Wye connection shown in FIGS. 10 and 11 the busbar 188 is positioned with apertures, preferably three in number, forcoupling together the motor neutral leads T4, T5 and T6.

As used herein, the term top is intended to mean the top face 160 of thepower conduit assembly 24 as viewed in FIGS. 2-6. It is intended thatsuch specific face of the power conduit assembly 24 may be indexed toanother orientation whereat another face or faces of the power conduitbox is vertically above the top face.

FIG. 8 shows schematically a typical electrical coupling configurationat the motor while FIGS. 9 through 11 illustrate the mechanical couplingfor Delta and Wye connections within the power conduit assembly 24.FIGS. 12 and 13 are electrical schematics of these couplings within thepower conduit assembly 24.

Reference is now made to the specific stator winding diagram of FIG. 7which is of a four pole, two circuit, three phase, independentconnection configuration. All leads with the same symbols connecttogether and it is intended that five slots be utilized for each polefor each phase. The leads from the stator windings through the slotspass as indicated to the power conduit assembly 24 and are coupled tothe three conductive terminals in the configuration shown in FIGS. 8through 11. The numerals on the leads correspond with those in theelectrical schematic diagram of FIG. 8. The arrangement of these leadswithin the power conduit assembly 24 are shown schematically in FIGS. 12and 13 with the three inductor symbols corresponding to the threecircuits of wires around the stator representing the three phases ofwindings.

Accessories Conduit Box

The accessories conduit box 20 can readily be seen in greater detail byviewing FIGS. 20 and 21. In these Figures, the accessories conduit box20 is shown as having upper, lower, side, front and back sections 192,194, 196, 198, and 200, respectively, of sheet metal physically securedtogether as by welding. Smaller apertures are provided in the side panel39 of the motor frame assembly 12, and these apertures permit thepassage of probe and sensor wires from appropriate probes and sensorsinternal of the machine.

The front section 198 includes inturned flanges to thereby create anopening only slightly smaller in size than the entire front section 198of the accessories conduit assembly 20. The front section 198 is coveredwith a door 202 having an inturned flange at its lower end. The inturnedflange of the door is secured to one segment of a hinge 204 while theother segment of the hinge is secured to the lower section 194 adjacentthe inturned flange. With appropriate latches secured to the door at itsupper portion, opening and closing of the door is readily and easilyachieved.

Inside accessories conduit box 20, there are vertically extendingpartitions 206, 208 and 210 as of sheet metal to physically divide thechamber within the accessories conduit box into a plurality of zones, orcompartments, for example 212, 214, 216, and 218. By way of exampleonly, a compartment 212 at the left end as viewed in FIG. 20 may bepermanently wired so as to couple proximetors therein to probes locatedat the bearing assemblies 26 for the purpose of determining vibrationsat each bearing assembly.

A second compartment 214 is for various signal leads and constitutes thesignal lead compartment. These leads are typically under 50 volts andmay power bearing thermocouples for temperature sensing and operatebearing and stator resistive temperature devices.

A third compartment 216 is for the power lead terminals of 50 volts orgreater. These are used to power the heater elements as they aredescribed above, as well as for instance oil heaters, a stator windingthermostat, and differential pressure switches for air filters or anyother optional accessory devices requiring 50 volts or greater.

These two central compartments 214, 216 include insulating terminalblocks 226 having conductive terminals 228 whereby the leads from atleast the aforementioned accessory devices may be appropriately coupled,uncoupled or modified as may be desired or required because of theconfiguration of the motor in which they are utilized. The insulatingterminal blocks 226 are secured to the back of section 200 accessoriesconduit box 20 through a pair of wireways or conduits 230 and 232. Theconduits provide an opening through the second and third compartments214 and 216 and are exposed at their ends to the first and fourthcompartments 212 and 218, respectively.

The conduit 230 is for carrying signal leads and has an opened upperface through the compartment 214 but is closed at the compartment 216.The conduit 232 is closed in the first signal compartment 214 where theconduit 230 is open. Conduit 232 is open in the second or power conduitcompartment 216 where the conduit 230 is closed. In this manner theconduits of each compartment will have an open and a closed face. In thecompartment 216 for the higher power leads, the power leads will be inthe opened conduit. In the compartment with the signal leads, theconduit 230 will be open and the conduit 232 with the power leads willbe closed. This arrangement allows the appropriate power leads to beattached to the appropriate terminals of each chamber. The arrangementwill expose only those wires to be utilized at such compartment and topreclude inadvertent utilization of leads of improper voltage or origin.This arrangement will enhance the safety of any and all electricaldevices in which it is utilized.

A fourth compartment 218 may house a bearing temperature monitor whichis mounted in a rectangular cutout in the accessories conduit box 20.This monitor includes, on the external face of the door, light-emittingdiode-type readouts to display the temperature of the bearings at bothends of the motor. Alarm temperatures and trip temperatures may also beprovided as readouts for each bearing.

As described above, both the accessories conduit box 20 and powerconduit assembly 24 may both be positioned on a common side of the frameassembly 12. In that arrangement, the compartment 212 containing theproximetor probe terminations is eliminated. The proximetor probeterminations may be made in compartment 218 if the bearing temperaturemodules are deleted.

The present disclosure includes that contained in the appended claims aswell as that of the foregoing description. Although this invention hasbeen described in its preferred form or embodiment with a certain degreeof particularity, it is understood that the present disclosure of thepreferred form has been made only by way of example and that numerouschanges in the details of construction, fabrication and use andincluding the combination and arrangement of parts may be resorted to bythose skilled in the art without departing from the spirit and scope ofthe invention.

What is claimed is:
 1. A dynamoelectric machine comprising:a framehaving spaced end portions and side panels coupling said end portions,said end portions each having a lower support member and an upper endshield removably secured thereto; a stator fixedly mounted with respectto said frame; a rotor rotatable about its axis in operative proximityto said stator; a shaft rotatable about its axis and supporting saidrotor so as to be concurrently rotatable therewith, said shaft beingsupported adjacent its ends by said lower support members, said rotorand shaft being asymmetric about a plane passing radially therethroughmidway of said end portions; releasable coupling means for selectivelycoupling and uncoupling each said lower support member and said upperend shield from said end portions of said frame to facilitate theremoval and replacement of said rotor and said shaft either frontward orbackward with respect to said stator and said frame; a generallyrectangular power conduit assembly having attachment means forreleasably attaching said power conduit assembly to one of said sidepanels, said power conduit assembly having an aperture therein incommunication with a correspoding aperture in said one side panel toallow the passage of leads between the interior of said frame, saidpower conduit assembly and the interior of said power conduit assemblyalso including an additional aperture to allow the passage of leadsbetween the interior of said power conduit assembly and a source ofelectrical power, said attachment means adapted to couple said powerconduit assembly to said one side panel with said additional aperturefacing selectively either upwardly, or downwardly or to either side; andan accessories conduit box fixedly secured to another of said sidepanels and including sensor means for monitoring selected operatingparameters of the dynamoelectric machine, a plurality of insulatingterminal blocks within said accessories conduit box each with conductiveterminals receiving leads coupled to said sensor means, and separationmeans for isolating said terminal blocks and said terminals within aplurality of electrically discrete compartments within said accessoriesconduit box, at least some of said compartments being adapted to supportsaid terminal blocks and terminals only of a predetermined electriccharacteristic.
 2. The dynamoelectric machine of claim 1 furthercomprising heater means within said frame for dissipating moisturetherein, said heater means including a plurality of low temperature,constant temperature elements encased within heat sinks so that the heatoutput thereof will not exceed a predetermined maximum temperature.
 3. Adynamoelectric machine comprising:a fixed stator; a rotor rotatablyassociated with said stator; a shaft supporting said rotor andconjointly rotatable therewith; end portions located adjacent oppositeends of said shaft to maintain said shaft and said rotor in apredetermined orientation with respect to said stator, said end portionshaving releasable coupling means for releasably coupling and uncouplingsaid rotor and said shaft from said end portions to facilitate theremoval and replacement of said shaft and said rotor with respect tosaid stator, said rotor being essentially symmetric about a planepassing axially therethrough midway between said end portions so thatsaid rotor may be selectively placed within the dynamoelectric machineeither frontwards or backwards with respect to said stator; and said endportions each including a shaft support member and an end shieldassociated with said releasable coupling means so as to be separablefrom said end portions, each said end shield including window means forviewing internally of the dynamoelectric machine.
 4. The dynamoelectricmachine as set forth in claim 3 wherein said window means is locatedadjacent said shaft, and the dynamoelectric machine further comprising abearing assembly at each end portion, each bearing assembly having aviewing aperture therein, said window means being generally aligned withsaid viewing apertures, respectively.
 5. The dynamoelectric machineassembly as set forth in claim 3 further comprising a power conduitassembly arranged to couple electrical leads from a source of electricalpower to other leads from within the dynamoelectric machine to powersaid stator.
 6. The dynamoelectric machine assembly as set forth inclaim 3 further comprising an accessories conduit box arranged tosupport leads from devices for controlling and monitoring thedynamoelectric machine.
 7. In a dynamoelectric machine having a stator,a rotor rotatable with respect to the stator, and a shaft havingopposite ends and supporting the rotor so as to be conjointly rotatabletherewith, an improved support assembly comprising:bearings forsupporting the shaft adjacent its opposite ends; a frame having sidepanels secured thereto and end portions supporting said bearings, theshaft and the rotor, each end portion having a shaft support and an endshield releasably coupled to, and uncoupled with respect to, said eachend portion to facilitate the removal and replacement of the rotor andthe shaft, and said end shields each having a window therein to viewsaid bearings; and said bearings being retained by said shaft supportsin fixed positions with respect to the shaft independent of theuncoupling of each end shield from a corresponding one of said endportions.
 8. In the dynamoelectric machine as set forth in claim 7wherein said bearings are end to end interchangeable with the shaft. 9.In the dynamoelectric machine as set forth in claim 7 wherein saidbearings include rotatable oil splash rings.
 10. In the dynamoelectricmachine as set forth in claim 11 wherein said bearings each include aviewing aperture generally aligned with said windows to permit viewingof said oil splash rings.